JPS6054262A - Method for controlling and monitoring cylinder speed of injection molding machine - Google Patents

Abstract

PURPOSE:To correct the change rate of a cylinder speed or stop a device and to prevent generation of a product defect and accident by comparing the detected change rate and set change rate and judging abnormality. CONSTITUTION:The change rate of an injection cylinder 10 to be changed by adjusting the rate of the liquid supplied to or discharged from the cylinder 10 by a liquid flow control valve 29 is measured. The measured change rate is compared with the set change rate of a cylinder speed. The set change rate is converted from the characteristic to increase or decrease the flow rate specific to a liquid pressure circuit including the valve 29 and the cylinder 10. The case in which the measured change rate described above and the set change rate are different is judged to be abnormality. A minor disorder is thus corrected and said disorder is large, the injection molding is stopped and the generation of a product defect and accident is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Misfire BJJ relates to a method of monitoring injection control of an injection cylinder that advances a pusher tip of a shot plunger in an injection molding apparatus such as a die casting machine or an injection molding machine 414.

In general, in injection molding such as die casting, there is a need for molds.
Depending on the shape and volume of the cavity, the temperature of the mold, etc.
The injection speed and injection pressure of molten metal must be determined appropriately. If the injection speed, injection pressure, etc. are inappropriate, the flow of the metal into the cavity will be poor, which may cause chips or cavities in the cast product, or the dimensional accuracy will reduce the product strength. This is because various adverse effects may occur in some cases.

By the way, shot plunger shot IJ, J velocity (V)
teeth.

For example, as shown in FIG. 1, two periods can be broadly divided into an initial low injection speed V] and a latter high injection speed V2. In this initial low-speed injection speed section, the molten metal is filled into the injection sleeve, and the plunger tip pushes the molten metal into the cavity and the molten metal is injected from the molten metal inlet force 1 at the tip of the trowel to the outside of the injection sleeve. In order to prevent the molten metal from spouting out, when the molten metal reaches one cavity, it will spout from the narrow gap into the relatively wide cavity, and the scum (air) in the cavity will mix with the molten metal. In order to prevent this, the molten metal is injected at low pressure and low speed, and in the high injection speed section, after the molten metal reaches the cavity, the light is adjusted inside the hot water cavity to prevent product defects and dimensions. ＼ Molten metal is injected at high pressure and high speed to prevent deterioration of process accuracy.

The injection time of the molten metal in the injection molding apparatus, including the low injection speed V1 and the high injection speed V28, is generally as short as a few seconds.In particular, the rise time from the low injection speed Vl to the high injection speed V2 is several hundredths of a second to a few hundredths of a second. Because the injection time is extremely short, only a few tens of seconds, conventionally, for example, high-speed injection injection pressure was measured and monitored.
In order to prevent the above-mentioned products from being missing, cavities occurring, deterioration of accuracy, etc., the hydraulic pressure of the hydraulic oil has not been corrected.

Abnormal modulation of the injection speed caused by such things as force), galling of the plunger tip, etc., is often insufficient to be measured at a fixed point in a constant speed section, and there is a drawback that the abnormality cannot necessarily be detected accurately.

Unexploded uA improves the above-mentioned measurement and abrasion at a fixed point and measures a predetermined section, that is, the rise section from low injection speed Vl to high injection speed V2, to detect abnormal conditions, and corrects minute modulations. , a cylinder injection control and monitoring method for an injection molding machine, which stops injection molding in case of large modulation.

In the present invention, as shown in FIG.
The plunger tip 1G at the tip of the plunger tip 1G is slidably provided in the injection sleeve, and the position and speed of the plunger tip 16 are detected by the injection cylinder 104 that moves the plunger tip 16 back and forth.]-Detection of the position of the cylinder rod 11 A speed detector 22 and a speed detector 218 are provided.

The position detection signal emitted from the position detector 22 is sent to the position calculator 24, and the position calculator 24 calculates the stroke LJ position of the injection cylinder 10 based on the level position detection signal. When the cylinder rod 11 reaches the predetermined position f set to n, the hydraulic pump 307
A rising signal is transmitted from 711 to a control device I for flow rate control discrimination provided in the hydraulic circuit to the injection cylinder io. The position setting device 23 is used to set the rising position from the low injection speed v1 to the high injection speed 2, which is the extrusion speed of the molten metal, and the position setting device 23 detects the set position signal and 1 position emitted from the molten metal extrusion speed. Based on the position detection signal E emitted from the cylinder 22), the position calculator 24 compares the measured position signal calculated in the position calculator 24 and sets the cylinder at the position set by the position setting device. When the first rod reaches the position, as shown in the separate diagram of the position calculator, the value of the low injection speed Vl,
The control device 27 is capable of arbitrarily setting the value of the time required for rising to the high speed v2 (x), so that 16 is reached with the set required time χ for rising when receiving the above-mentioned rising signal. The opening of the flow rate control discrimination is opened to control the continuous hole.

Here, the flow rate control discrimination is, for example, a flow rate of 4 inches and 1 line driven by a pulse motor as shown in FIG.

In the flow rate control 29i shown in FIG. 5, 41 is a valve body having a hydraulic oil inlet C for the internal force 1 and the hydraulic oil outlet S (in the direction perpendicular to the axis), and 44 is a valve body in the valve body 41. The valve stool @ 4j that moves in the axial direction is connected to the rear part of the valve spool 44, and the nut shaft 46 is screwed into the internal axis bar 1s of the nut shaft 45 by a ball screw 47f. A pinion gear 48 is meshed with a rear gear 49 of the screw shaft 46.

56 is a pulse motor whose rotation amount can be controlled; 51 is a key; the valve spool 44 is
moves back and forth in the axial direction to instantaneously open and close the valve and adjust the opening degree to control the flow rate. As described above, this flow rate control valve 29 is arranged in a cylindrical valve body 41 having a hydraulic oil inlet 42 at the end surface in the axial direction and a hydraulic oil outlet 43 at the side surface, and a valve spool 44 connected to the pulse motor. This device controls the flow rate by driving the valve spool 44 in the axial direction by the action of 1. The flow rate is controlled by rapidly reducing the axial thrust of the valve spool 44 caused by the hydraulic oil in response to the increase in the opening amount and moving speed of the valve spool 44. High-speed switching requires
The i-force is reduced by 8, and the flow rate can be switched at high speed by flow rate control discrimination.

In this flow rate control discrimination, the rotation amount T7 of the pulse motor group is determined by the command signal f of the flow rate control valve controller @27. (
That is, the opening amount of the valve spool is determined by the rotation angle l, and the flow rate to the injection cylinder io is controlled, and the rate of change in the flow rate is determined by the magnitude of the rotational speed during the rotation of the pulse motor. The rising state of the speed is determined.

In addition, in the flow rate control discrimination with such a structure and operation, the time from when the command to change the speed is received until the valve spool 44 actually starts to open) L18 - maximum j, mm seconds or less can be pushed by the ship. The response is extremely good compared to conventional flow control valves.

In addition, the operability and operational precision of valve opening and closing have also been significantly improved.

A permanent magnet 52 is fixed to a part of the surface of the nut shaft, and a part of the opposite casing 53 is fixed to a permanent magnet 52.
For example, a position detecting device 54 using a magnetic action such as a cello cross sensor and a magnetic force is installed. The position detector 54 is a proximity switch that is sensitive to the movement of the permanent magnet 52, so that the distance traveled in the axial direction of the shaft shaft and the valve spool 44 can be accurately detected and fed back to the control device. There is. Further, the zero position of the valve spool 44 is electrically detected by the action of the permanent magnet 52 and the position detector, and the pulse motor (pulse motor) is accurately stopped at that position via the flow rate control valve control device 27. I want to be able to -C.

As the 1-position detector 54, one having an angle of 8 degrees 001~ is used.

The speed of the injection cylinder IO is controlled using the flow rate control valve 29 having the structure as described above, and on the other hand, the speed detector 21 of the cylinder rod 11 is provided to detect the injection speed of the molten metal, that is, the speed of the plunger tip 16. The speed detection signal is sent to the speed calculator section, and the speed calculator 25I calculates the injection speed of the plunger tip based on the speed detection signal f, and sends it as a measured speed signal to the speed calculator section.

The measured speed signal is inputted to this speed comparator section from the speed calculator section, as well as the above-mentioned rising signal sent from the position calculator 24 to the control device η, and the above-mentioned rising signal sent from the control device n to the control device η. Confidence between the set rising time l-1 and the set high-speed injection speed ■2 @! J5 people are working hard. The speed comparator 26 compares the set high-speed injection speed signal from the control device n with the measured speed signal from the speed calculator section, and determines that the injection speed of the plunger tip 16 is the set high-speed injection speed V21.
The position calculation unit 24 calculates the point in time when the
The time required for the injection speed of the plunger tip 16 to reach the set high-speed injection speed V2 from the reception of the rising signal from 1-
k (see Figure 4), and the measured required time i
1 (and the set rise time required A based on the set rise time required signal l transmitted from the control device n).

This speed comparator 26 has a set rising time 1i.
On the other hand, if the measured required time k is long, set the required rise time i-6 to shorten the opening/closing speed of the flow control valve at the next injection. It sends a correction signal to the control device η, and the measured required time il (is the set rising time required -
If t and i are too long, an alarm signal is sent to the alarm device to stop the operation of the injection cylinder 10, and the injection operation is appropriately stopped by the operation of the alarm device.

The flow rate control valve 29i is installed in the oil supply circuit to the piston rear chamber t2 of the injection cylinder 10 as shown in FIG. 1
A drain circuit is provided from the cylinder 3 to the oil tank 31 to control the amount of oil discharged from the injection cylinder lO.
In some cases, the speed of 1 is controlled.

In addition, the required startup time 411 of the control valve control device n
Regarding this, as shown in FIG. 4, various characteristics of the start-up delay time 11 and start-up completion time 54 of the injection cylinder 101 were first measured, and the plunger tip was measured when the flow rate control valve 29 was operated. 16, that is, the followability of the molten metal injection speed. This is the time required for rise, which is generally an extremely short time of several tens to hundreds of milliseconds, and in this short time, the low speed force of If-G is several tens of seconds. . Because of the sudden acceleration to a high speed, the injection cylinder io
A start-up delay time occurs due to the viscosity and compressibility of the pressurized oil to be operated and the inertia of the pressurized oil and other mechanically moving parts, and the characteristics of this start-up delay time 11 and the required time Once the hydraulic circuit system of the cylinder 10 is determined, it is uniquely determined.

To f3r, the difference in time required for rising is determined by the speeds Vl, V2. ．． A speed change pattern that matches the rise degree, more preferably, can be predetermined as a function of the pressure and temperature of the hydraulic fluid.

In this way, the flow rate control valve controller 271 sets the low injection speed Vl, the high injection speed V2, and the required rise time Z-6 according to the characteristics grasped in advance, and the speed comparator 261 sets the required rise time as described above. Compare the time (2) with the measurement start-up time (Lk). A1 is the measurement start-up time (il) with respect to the set start-up time (1i). An abnormality of 10 indicates an increase in resistance by 1 to the advancement of the granger tip, that is, the advancement of the cylinder mid 11, and it can be determined that an abnormality has occurred in the injection molding apparatus.

In addition, the comparison of the above-mentioned set rise time and measured rise time (21) is made by comparing the start-up completion time f:, but the required start-up time i1 is also measured and set value. Can be compared with ?J-.

The comparison between the measured value and the set value also takes into account the safety factor of the injection molding equipment.For example, if the measured value is 100% higher than the set value
If the abnormality is between % (matching state) and less than 105%, no correction is required, and the injection molding may be repeated and continued.
Since the abnormality is minor (Z), a correction signal is sent from the speed comparator 26 to the control valve control device 271 to shorten the set rise time λ to continue injection molding. If it is less than 120% to 130%, a correction signal will be sent to the control valve control device #27I, and an alarm signal will be sent to each alarm device to notify the abnormality. 1 if the required time is 130% or more? Second, accidents can be prevented from occurring by determining that the abnormality is serious and causing an emergency stop of the injection molding apparatus.

In addition, it is generally said that the faster the rise speed is at least 3%, the better, so if the measured rise time is less than 100 inches of the set rise time, there is no need to make any corrections, or , you may modify it so that it is 100% 1. However, it is best to consider the 100% of the rising rate of change as the limit of the opening speed of the flow rate control valve z9.

As described above, the present invention adjusts the amount of liquid supplied to the cylinder IO or the amount of liquid discharged from the cylinder IO by flow control discrimination, and changes the cylinder speed from a desired low injection speed Vl to a desired high injection speed V2). In case of tightening.

The rate of change in cylinder speed, that is, the pattern of speed change, is detected as the measurement start-up time 4, and the measured rate of change is determined by the flow rate increase/decrease characteristics specific to the hydraulic circuit system including the flow rate control valve 29 and the cylinder 10. Set start-up time converted from A7. Compared with the set rate of change of cylinder speed,
7. A method for monitoring cylinder speed control of an injection molding apparatus, characterized in that an abnormality is determined when C differs from IJ to the measured rate of change.

In this way, the difference between the measured change rate and the set change rate converted from the flow rate increase/decrease characteristic force, that is, the delay n, is used to detect abnormalities such as an increase in resistance applied to the plunger tip 16, etc. This is a method that can easily identify abnormalities.

In addition, the measured rate of change is divided into dark values such as 100% to less than 105%, 105% to less than 120%, and 120 or higher, and the measured rate of change is compared to the set rate of change). If the measured rise time is equal to the set rise time, or is less than about 1 (') 5 times the measured change rate, repeat the injection molding without making any corrections. , the measured rate of change is approximately the set rate of change]05 to 1
If it is less than 20 inches.

By adjusting the degree of opening change of flow control discrimination,
Achieving the desired ejection rate change of 7fr from the ship by modifying it to shorten the standing time, that is, to increase the rate of change.
It is a method that can efficiently prevent various product defects such as chipping of injection molded products, occurrence of cavities, and decrease in dimensional accuracy.In addition, the measured rate of change is approximately 120% or more compared to the set rate of change, which is very slow.
This is a useful method that can prevent accidents by issuing an alarm and closing the flow control valve 29 to stop the injection molding equipment.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an outline of the injection speed of the cylinder in one injection molding machine, Fig. 2 is a block diagram for implementing the method according to the invention, Figs. It is a diagram showing changes. 10 - injection cylinder, 1] = cylinder rod. 14-injection sleeve, 15-injection plunger, 16=plunger tip, 21-speed detector, 22-position detector, illusion=position setter, 24-position calculator, 25=speed calculator, ga-speed comparator , 27-Flow rate control valve control device, 28=Wireless information device, 29-Flow rate control valve, (capital)-
Hydraulic pump, blade/crus motor. Patent Applicant Ube Industries Co., Ltd. No. 2, Name of the invention: Cylinder speed control monitoring method for injection molding equipment 3, Relationship to the case involving the person who performs auxiliary JE Patent applicant: 1-12-:32 Nishiki-cho, Ube City, Yamaguchi Prefecture (020) Ube Industries Co., Ltd. 4. AgentShowa 5, 2-14-10-707 Sangenjaya, Setagaya-ku, Tokyo
August 5, 1986, column 7 of the "Brief explanation of the drawings" stated in the subject of amendment (1) Specification-), Contents of the amendment (1) "Brief explanation of the drawings" stated in the description In the column, page 18, line 6 of the specification states, "This is a diagram showing changes in injection speed."'
r 51iJ is a diagram showing an example of a flow control valve used in the present invention. Revised to J 11: Yes.

Claims (1)

[Claims] (11 The amount of liquid supplied to the cylinder or the amount of liquid discharged from the cylinder is adjusted by a flow control valve, and the cylinder speed is adjusted to a desired value l.
If this is to be changed, the rate of change in cylinder speed is detected, and the measured rate of change is converted from the flow rate increase/decrease characteristic force unique to the hydraulic circuit system including the liquid volume control valve and the cylinder. A method for monitoring cylinder speed control in an injection molding apparatus, characterized in that the measured rate of change is compared with a set rate of change in speed, and if the measured rate of change is different from the set rate of change, it is determined that there is an abnormality. (2) Determine the degree of abnormality by identifying the degree of difference between the measured cylinder speed change rate and the cylinder speed change rate converted from the flow rate increase/decrease characteristics according to multiple open values. A cylinder speed control monitoring method for an injection molding apparatus according to claim 1, characterized in that: (3) If the degree of difference between the measured rate of change in cylinder speed and the rate of change in cylinder speed converted from the flow rate increase/decrease characteristic is small, by adjusting Gu, the rate of change in opening of the flow control valve, Obtain the speed change of the cylinder whose power was cut off beforehand.1. A cylinder speed control monitoring method for an injection molding apparatus according to claim 1 or 2, characterized in that the cylinder speed control and monitoring method of an injection molding apparatus is stabilized so that the speed of the injection molding apparatus is stabilized. (4) If the difference between the measured rate of change in cylinder speed and the rate of change in cylinder speed converted from the flow rate increase/decrease characteristics is large, immediately disconnect the hydraulic circuit system and the hydraulic pressure supply source. Cylinder speed control monitoring of an injection molding apparatus (d) according to claim 1 or 2, wherein the hydraulic circuit system is maintained. (5) The rate of change of the measured cylinder speed is converted from the flow rate increase/decrease characteristic.
Cylinder speed control monitoring of an injection molding apparatus according to claims 1 to 4, characterized in that the maximum value of the setting change rate is determined so as to be about 20%. Method.